Hey Folks,
I have an 02 E430. Recently I came across the issue with ABS, ESP, BAS Warning Lights with Faulty Brake Light Indicator coming up on my dash. The problem was intermittent, then became a hard fault. I started by changing the brake switch, however that was not the cause of the faults. The car would fire the code as soon as I pressed the brake pedal. I would get the faults and my brake lights would stop working. I've seen MANY threads on the internet with individuals with similar cars complaining about this issue. I was able to narrow down the issue to the actual 'headlight switch'. I swapped the headlight switch for a new one, it was roughly $250 CDN. The lights all disappeared and my brake lights began working again. The car went to about 6 different mechanics before it was diagnosed. MB wanted to change my ABS module, however I was certain that was not the issue. Nonetheless, if you encounter this particular issue, your 'headlight switch' can be a likely culprit.
Cheers,
Ricky P.

I regularly had those brake related lights come on, but after installing new battery I have not seen them. I imagine there could be various causes, especially ones that reduce voltages like bad contacts or grounds.